Cisco Cisco Email Security Appliance C160 Mode D'Emploi

The 

random

 rule generates a random number from zero to N-1, where N is the integer value supplied in 

parenthesis after the rule. Like the 

header()

 rule, this rule may be used in a comparison, or may be used 

alone in a “unary” form. The rule evaluates to 

true 

in the unary form if the random number generated 

is non-zero. For example, both of the following filters are effectively equal, choosing Virtual Gateway 
address A half the time, and Virtual Gateway address B the other half of the time: 

The 

rcpt-count

 rule compares the number of recipients of a message against an integer value, in a 

similar way to the 

body-size

 rule. This can be useful for preventing users from sending email to large 

numbers of recipients at once, or for ensuring that such large mailing campaigns go out over a certain 
Virtual Gateway address. The following example sends any email with more than 100 recipients over a 
specific Virtual Gateway address:

load_balance_a:

   if (random(10) < 5) {

        alt-src-host('interface_a');

   } else {

        alt-src-host('interface_b');

   }

load_balance_b:

   if (random(2)) {

       alt-src-host('interface_a');

   } else {

       alt-src-host('interface_b');

   }

large_list_filter:

   if (rcpt-count > 100) {

        alt-src-host('mass_mailing_interface');

   }